Wear detection for elevator system belt

ABSTRACT

A belt for an elevator system includes a plurality of tension members arranged along a belt width and extending longitudinally along a length of the belt, each tension member including a plurality of fibers. A metallized coating layer is applied to at least a portion of an outer surface of at least one tension member of the plurality of tension members. The metallized coating has a coating electrical conductivity greater than a tension member electrical conductivity of the at least one tension member. A jacket material at least partially encapsulates the plurality of tension members and the metallized coating layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of 62/595,158, filed Dec. 6, 2017,which is incorporated herein by reference in its entirety.

BACKGROUND

The subject matter disclosed herein relates to elevator systems. Moreparticularly, the present disclosure relates wear detection of elevatorsystem belts, such as those having non-metallic load bearing members.

Elevator systems are useful for carrying passengers, cargo, or both,between various levels in a building. Some elevators are traction basedand utilize load bearing members such as belts for supporting theelevator car and achieving the desired movement and positioning of theelevator car.

Where a belt is used as a load bearing member, a plurality of tensionmembers, or cords, are embedded in a common jacket. The jacket retainsthe cords in desired positions and provide a frictional load path. In anexemplary traction elevator system, a machine drives a traction sheavewith which the belts interact to drive the elevator car along ahoistway. Belts typically utilize tension members formed from steelelements, but alternatively may utilize tension members formed fromsynthetic fibers or other non-metallic materials, such as carbon fibercomposites.

In a carbon fiber composite tension member, the members have goodstrength to weight characteristics, but typically have reduced hightemperature performance compared to tension members formed from steelwires. It is desired to monitor the belt for wear and/or damage duringits operating life.

BRIEF DESCRIPTION

In one embodiment, a belt for an elevator system includes a plurality oftension members arranged along a belt width and extending longitudinallyalong a length of the belt, each tension member including a plurality offibers. A metallized coating layer is applied to at least a portion ofan outer surface of at least one tension member of the plurality oftension members. The metallized coating has a coating electricalconductivity greater than a tension member electrical conductivity ofthe at least one tension member. A jacket material at least partiallyencapsulates the plurality of tension members and the metallized coatinglayer.

Additionally or alternatively, in this or other embodiments the at leastone tension member is formed from the plurality of fibers suspended in athermoset matrix material.

Additionally or alternatively, in this or other embodiments theplurality of fibers are formed from one or more of, glass, liquidcrystal polymer, basalt, polyester, nylon or aramid materials.

Additionally or alternatively, in this or other embodiments theplurality of fibers are formed from carbon fibers.

Additionally or alternatively, in this or other embodiments the tensionmember electrical conductivity is in the range of 10⁻²¹ to 10⁵ siemensper meter.

Additionally or alternatively, in this or other embodiments the coatinglayer is formed from one or more of electrically conductive materialswith conductivity greater than 10⁶ siemens per meter.

Additionally or alternatively, in this or other embodiments the coatinglayer is formed from one or more paramagnetic materials.

Additionally or alternatively, in this or other embodiments the coatinglayer completely covers an outer perimetrical surface of the at leastone tension member.

In another embodiment, a method of health monitoring of a belt of anelevator system includes connecting a health monitoring unit to a beltof an elevator system. The belt includes a plurality of tension membersarranged along a belt width and extending longitudinally along a lengthof the belt, each tension member including a plurality of fibers. Ametallized coating layer is applied to at least a portion of an outersurface of at least one tension member of the plurality of tensionmembers. The metallized coating has a coating electrical conductivitygreater than a tension member electrical conductivity of the at leastone tension member. A jacket material at least partially encapsulatesthe plurality of tension members and the metallized coating layer. Avoltage is applied across the metallized coating layer of the at leastone tension member via the health monitoring unit, and one or moreelectrical properties are evaluated at the health monitoring unit. Theone or more electrical properties are indicative of a health conditionof the belt.

Additionally or alternatively, in this or other embodiments the one ormore electrical properties are one or more of electrical resistance orcontinuity.

Additionally or alternatively, in this or other embodiments an opencircuit detected by the health monitoring unit is indicative of adamaged or broken tension member.

Additionally or alternatively, in this or other embodiments magneticinduction is utilized to measure a thickness of the jacket material,wherein the metallized coating layer comprises one or more paramagneticmaterials.

Additionally or alternatively, in this or other embodiments a baselineelectrical resistance is measured across the metallized coating layervia the health monitoring unit, and a subsequent electrical resistanceis measured across the metallized coating layer after a predeterminedtime via the health monitoring unit. A change in electrical resistancefrom the baseline electrical resistance to the subsequent electricalresistance is indicative of wear of or damage to the jacket material.

Additionally or alternatively, in this or other embodiments themetallized coating layer is applied to the tension member via one of acold spray or an electrodeposition process.

In yet another embodiment, an elevator system includes a hoistway, anelevator car located in the hoistway, and a belt operably connected tothe elevator car to suspend and/or drive the elevator car along thehoistway. The belt includes a plurality of tension members arrangedalong a belt width and extending longitudinally along a length of thebelt, each tension member including a plurality of fibers. A metallizedcoating layer is applied to at least a portion of an outer surface of atleast one tension member of the plurality of tension members. Themetallized coating has a coating electrical conductivity greater than atension member electrical conductivity of the at least one tensionmember. A jacket material at least partially encapsulates the pluralityof tension members and the metallized coating layer.

Additionally or alternatively, in this or other embodiments at the leastone tension member is formed from the plurality of fibers suspended in athermoset matrix material.

Additionally or alternatively, in this or other embodiments theplurality of fibers are formed from one or more of glass, liquid crystalpolymer, basalt, polyester, nylon or aramid materials.

Additionally or alternatively, in this or other embodiments theplurality of fibers are formed from carbon fibers.

Additionally or alternatively, in this or other embodiments the tensionmember electrical conductivity is in the range of 10⁻²¹ to 10⁵ siemensper meter.

Additionally or alternatively, in this or other embodiments the coatinglayer is formed from one or more of electrically conductive materialswith conductivity greater than 10⁶ siemens per meter.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter is particularly pointed out and distinctly claimed atthe conclusion of the specification. The foregoing and other features,and advantages of the present disclosure are apparent from the followingdetailed description taken in conjunction with the accompanying drawingsin which:

FIG. 1 is a schematic view of an exemplary elevator system;

FIG. 2 is a cross-sectional view of an embodiment of a belt for anelevator system;

FIG. 3 illustrates an embodiment of a tension element for a belt of anelevator system;

FIG. 4 schematically illustrates application of an embodiment of acoating layer to a tension element; and

FIG. 5 schematically illustrates health monitoring of an embodiment ofan elevator system belt.

DETAILED DESCRIPTION

A detailed description of one or more embodiments of the disclosedapparatus and method are presented herein by way of exemplification andnot limitation with reference to the Figures.

Shown in FIG. 1, is a schematic view of an exemplary traction elevatorsystem 10. Features of the elevator system 10 that are not required foran understanding of the present invention (such as the guide rails,safeties, etc.) are not discussed herein. The elevator system 10includes an elevator car 12 operatively suspended or supported in ahoistway 14 with one or more belts 16. The one or more belts 16 interactwith one or more sheaves 18 to be routed around various components ofthe elevator system 10. The one or more belts 16 could also be connectedto a counterweight 22, which is used to help balance the elevator system10 and reduce the difference in belt tension on both sides of thetraction sheave during operation.

The sheaves 18 each have a diameter, which may be the same or differentthan the diameters of the other sheaves 18 in the elevator system 10. Atleast one of the sheaves could be a traction sheave 52. The tractionsheave 52 is driven by a machine 50. Movement of drive sheave by themachine 50 drives, moves and/or propels (through traction) the one ormore belts 16 that are routed around the traction sheave 52. At leastone of the sheaves 18 could be a diverter, deflector or idler sheave.Diverter, deflector or idler sheaves are not driven by a machine 50, buthelp guide the one or more belts 16 around the various components of theelevator system 10.

In some embodiments, the elevator system 10 could use two or more belts16 for suspending and/or driving the elevator car 12. In addition, theelevator system 10 could have various configurations such that eitherboth sides of the one or more belts 16 engage the one or more sheaves 18or only one side of the one or more belts 16 engages the one or moresheaves 18. The embodiment of FIG. 1 shows a 1:1 roping arrangement inwhich the one or more belts 16 terminate at the car 12 and counterweight22, while other embodiments may utilize other roping arrangements.

The belts 16 are constructed to have sufficient flexibility when passingover the one or more sheaves 18 to provide low bending stresses, meetbelt life requirements and have smooth operation, while beingsufficiently strong to be capable of meeting strength requirements forsuspending and/or driving the elevator car 12.

FIG. 2 provides a cross-sectional schematic of an exemplary belt 16construction or design. The belt 16 includes a plurality of tensionmembers 24 extending longitudinally along the belt 16 and arrangedacross a belt width 26. The tension members 24 are at least partiallyenclosed in a jacket material 28 to restrain movement of the tensionmembers 24 in the belt 16 and to protect the tension members 24. Thejacket material 28 defines a traction side 30 configured to interactwith a corresponding surface of the traction sheave 52. Exemplarymaterials for the jacket material 28 include the elastomers ofthermoplastic and thermosetting polyurethanes, polyamide, thermoplasticpolyester elastomers, and rubber, for example. Other materials may beused to form the jacket material 28 if they are adequate to meet therequired functions of the belt 16. For example, a primary function ofthe jacket material 28 is to provide a sufficient coefficient offriction between the belt 16 and the traction sheave 52 to produce adesired amount of traction therebetween. The jacket material 28 shouldalso transmit the traction loads to the tension members 24. In addition,the jacket material 28 should be wear resistant and protect the tensionmembers 24 from impact damage, exposure to environmental factors, suchas chemicals, for example.

The belt 16 has a belt width 26 and a belt thickness 32, with an aspectratio of belt width 26 to belt thickness 32 greater than one. The belt16 further includes a back side 34 opposite the traction side 30 andbelt edges 36 extending between the traction side 30 and the back side34. While eight tension members 24 are illustrated in the embodiment ofFIG. 2, other embodiments may include other numbers of tension members24, for example, 4, 6, 10 or 12 tension members 24. Further, while thetension members 24 of the embodiment of FIG. 2 are substantiallyidentical, in other embodiments, the tension members 24 may differ fromone another. While the tension members 24 in the embodiment of FIG. 2are circular in cross-section, it is to be appreciated that othercross-sectional shapes, such as rectangular, oval, or other shapes, maybe utilized in other embodiments.

Referring now to FIG. 3, the tension members 24 include a plurality offibers 40 bonded to a polymer matrix 42 to form the tension members 24.The fibers 40 are continuous or discontinuous or combination ofcontinuous and discontinuous over the belt 16 length and, orientedgenerally such that a fiber 40 length is directed along the belt 16length. The fibers 40 may be formed of one or more of a number ofmaterials, such as carbon, glass, liquid crystal polymer, basalt,polyester, nylon, aramid or other polyimide materials. Further, thefibers 40 may be organized into a grouping, such as a spun yarn. Thematrix 42 may be formed of, for example a thermoset or thermoplasticmaterial. The tension member 24 is further configured to have a fiber 40density of 30% to 70% fibers 40 per unit of volume. In some embodiments,the fibers 40 may vary in size, length or circumference and may furtherbe intentionally varied to provide a selected maximum fiber 40 density.In some embodiments, the tension members 24 may be formed as thinlayers, in some embodiments by a pultrusion process. In a standardpultrusion process, the load carrying fibers 40 are impregnated with thematrix material 42 and are pulled through a heated die and additionalcuring heaters where the matrix material 42 undergoes cross linking. Insome embodiments, a dry fiber construction is utilized in forming thetension member 24, with the dry fiber construction characterized by theabsence of the matrix material.

The tension members 24 based upon glass, liquid crystal polymer, basalt,polyester, nylon, aramid or other polymeric fibers have low electricalconductivity, for example, in the range of 10⁻⁶ to 10⁻²¹ siemens permeter. Tension members 24 based upon carbon fibers have higherelectrical conductivity, for example 10² to 10⁵ siemens per meter. Acoating layer 44 is applied to the tension members 24 as shown in FIG.2. The coating layer 44 is of a material having a higher electricalconductivity than the tension member 24, for example electricalconductivity greater than 10⁶ siemens per meter and may be a metallizedcoating including, but not limited to, copper, iron, nickel or othermetallic materials. Referring to FIG. 4, the coating layer 44 is appliedto the tension member 24 via, for example, a cold spray operation, oralternatively by another process such as electrodeposition. Thecomposition of the coating layer 44 also includes those based ongraphenes and similar nanostructured materials dispersed in a basepolymer provided that the electrical conductivity of the coating layeris greater than 10⁶ siemens per meter. In some embodiments, the coatinglayer 44 is applied over an entire external surface of the tensionmember 24, while in other embodiments the coating layer 44 is appliedonly to a selected surface or surfaces of the tension member 24.Referring again to FIG. 2, in the embodiment illustrated the coatinglayer 44 is applied to each of the tension members 24. In otherembodiments, the coating layer 44 may be applied to only selectedtension members 24 of the belt 16, for example, tension members 24closest to the belt edges 36, and/or tension members 24 nearest alateral center of the belt 16.

Referring now to FIG. 5, utilization of the coating layer 44 allows forhealth monitoring of the belt 16, in particular monitoring of thetension members 24 for breakage or damage, and wear of the jacketmaterial 28. The belt 16, in particular the coating layer 44, isconnected to a health monitoring unit 46. A voltage is applied acrossthe coating layer 44, and the result is indicative of a condition of thebelt 16 and/or the tension member 24. For example, a broken or damagedtension member 24 is detected as an open circuit. Further, wear of thejacket material 28 may be detected by the health monitoring unit 46.When the jacket material 28 wears or erodes, the coating layer 44 at oneor more tension members 24 contacts the sheave 18. In doing so, when thevoltage is applied to the coating layer 44 via the health monitoringunit 46 a resistance or continuity measured at the health monitoringunit 46 changes relative to the resistance or continuity measured whenthe coating layer 44 is not contacting the sheave 18. In suchapplications, a baseline resistance or continuity may be obtained whenthe coating layer 44 is not contacting the sheave 18, for example, whenthe belt 16 is new or entering service. Subsequent measured resistancesor continuity may be compared to the baseline measurement, and when achange is observed, such a change is indicative of the coating layer 44contacting the sheave 18, and thus evidence of a worn or damaged jacketmaterial 28.

Furthermore, if the coating layer 44 comprises a paramagnetic materialsuch as but not limited to iron and/or nickel, the thickness of thejacket material 28 can be directly measured using magnetic inductionmethods. Such a technique has been to detect partial wear of jacketmaterial 28. The integrity of the tension members 24 when coated with aparamagnetic material can be assessed using magnetic flux leakagetechniques described in prior art related to steel reinforced beltapplications.

While the present disclosure has been described in detail in connectionwith only a limited number of embodiments, it should be readilyunderstood that the present disclosure is not limited to such disclosedembodiments. Rather, the present disclosure can be modified toincorporate any number of variations, alterations, substitutions orequivalent arrangements not heretofore described, but which arecommensurate in spirit and/or scope. Additionally, while variousembodiments have been described, it is to be understood that aspects ofthe present disclosure may include only some of the describedembodiments. Accordingly, the present disclosure is not to be seen aslimited by the foregoing description, but is only limited by the scopeof the appended claims.

What is claimed is:
 1. A belt for an elevator system, comprising: aplurality of tension members arranged along a belt width and extendinglongitudinally along a length of the belt, each tension member includinga plurality of fibers; a metallized coating layer applied to at least aportion of an outer surface of at least one tension member of theplurality of tension members, the metallized coating having a coatingelectrical conductivity greater than a tension member electricalconductivity of the at least one tension member; and a jacket materialat least partially encapsulating the plurality of tension members andthe metallized coating layer.
 2. The belt of claim 1, wherein the atleast one tension member is formed from the plurality of fiberssuspended in a thermoset matrix material.
 3. The belt of claim 1,wherein the plurality of fibers are formed from one or more of, glass,liquid crystal polymer, basalt, polyester, nylon or aramid materials. 4.The belt of claim 1, wherein the plurality of fibers are formed fromcarbon fibers.
 5. The belt of claim 1, wherein the tension memberelectrical conductivity is in the range of 10⁻²¹ to 10⁵ siemens permeter.
 6. The belt of claim 1, wherein the coating layer is formed fromone or more of electrically conductive materials with conductivitygreater than 10⁶ siemens per meter.
 7. The belt of claim 1, wherein thecoating layer is formed from one or more paramagnetic materials.
 8. Thebelt of claim 1, wherein the coating layer completely covers an outerperimetrical surface of the at least one tension member.
 9. A method ofhealth monitoring of a belt of an elevator system, comprising:connecting a health monitoring unit to a belt of an elevator system, thebelt including: a plurality of tension members arranged along a beltwidth and extending longitudinally along a length of the belt, eachtension member including a plurality of fibers; a metallized coatinglayer applied to at least a portion of an outer surface of at least onetension member of the plurality of tension members, the metallizedcoating having a coating electrical conductivity greater than a tensionmember electrical conductivity of the at least one tension member; and ajacket material at least partially encapsulating the plurality oftension members and the metallized coating layer; applying a voltageacross the metallized coating layer of the at least one tension membervia the health monitoring unit; and evaluating one or more electricalproperties at the health monitoring unit, the one or more electricalproperties indicative of a health condition of the belt.
 10. The methodof claim 9, wherein the one or more electrical properties are one ormore of electrical resistance or continuity.
 11. The method of claim 9,wherein an open circuit detected by the health monitoring unit isindicative of a damaged or broken tension member.
 12. The method ofclaim 9, further comprising utilizing magnetic induction to measure athickness of the jacket material, wherein the metallized coating layercomprises one or more paramagnetic materials.
 13. The method of claim 9,further comprising: measuring a baseline electrical resistance acrossthe metallized coating layer via the health monitoring unit; andmeasuring a subsequent electrical resistance across the metallizedcoating layer after a predetermined time via the health monitoring unit;wherein a change in electrical resistance from the baseline electricalresistance to the subsequent electrical resistance is indicative of wearof or damage to the jacket material.
 14. The method of claim 9, whereinthe metallized coating layer is applied to the tension member via one ofa cold spray or an electrodeposition process.
 15. An elevator systemcomprising: a hoistway; an elevator car disposed in the hoistway; and abelt operably connected to the elevator car to suspend and/or drive theelevator car along the hoistway, the belt including: a plurality oftension members arranged along a belt width and extending longitudinallyalong a length of the belt, each tension member including a plurality offibers; a metallized coating layer applied to at least a portion of anouter surface of at least one tension member of the plurality of tensionmembers, the metallized coating having a coating electrical conductivitygreater than a tension member electrical conductivity of the at leastone tension member; and a jacket material at least partiallyencapsulating the plurality of tension members and the metallizedcoating layer.
 16. The elevator system of claim 15, wherein the at leastone tension member is formed from the plurality of fibers suspended in athermoset matrix material.
 17. The elevator system of claim 15, whereinthe plurality of fibers are formed from one or more of glass, liquidcrystal polymer, basalt, polyester, nylon or aramid materials.
 18. Theelevator system of claim 15, wherein the plurality of fibers are formedfrom carbon fibers.
 19. The elevator system of claim 15, wherein thetension member electrical conductivity is in the range of 10⁻²¹ to 10⁵siemens per meter.
 20. The elevator system of claim 15, wherein thecoating layer is formed from one or more of electrically conductivematerials with conductivity greater than 10⁶ siemens per meter.